View Compilation Error

0_0_32782374_22836.cpp:430:1: error: 'function' does not name a type
 function<int(db)> sign = Geo::sign;
 ^
0_0_32782374_22836.cpp:431:1: error: 'function' does not name a type
 function<int(db,db)> cmp = Geo::cmp;
 ^
0_0_32782374_22836.cpp: In function 'int main()':
0_0_32782374_22836.cpp:451:23: error: 'sign' was not declared in this scope
  if (sign(Geo::area(a)) == -1) reverse(seg(a));
                       ^
0_0_32782374_22836.cpp:451:23: note: suggested alternative:
0_0_32782374_22836.cpp:77:13: note:   'Geo::sign'
  inline int sign(db a) {return a < -eps ? -1 : a > eps;}
             ^